Localized theme

Move all translations related to the theme from fun-apps to this
repository.  Previously, these files were included in fun-apps. It makes
more sense to include them directly in the theme and to point to them
via the common settings file of fun-apps.

Also, flag all strings as translatable. Finally, translate
these strings in django.po.

The localization file can now be maintained via the makemessages_fun
command (in fun-apps).
Add "News" to nav menu

Style the various news sections.
Lighter top article news subtitle
Fix news list layout
Fix "s'inscrire maintenant" menu item

Menu item was too short.
Fix "Qu'est-ce que FUN ?" translation
Don't float news
News: set image ratios to 1.56
implement cookie banner in main.html and add cookie banner css and js files
add translation message in po file
change z-index to 9999
News: fix line issue
News: fix long title issue